198 



THE AGE OF MAMMALS 



The insectivores are represented by large numbers of a small aquatic 

 animal (Echinogale) allied to the desmans. The beavers are also abundant 

 here (Steneofiber eseri), animals about one-third smaller than the existing 

 beavers. The Herbivora are the preponderating element of the fauna. 

 Both the two-horned {Dicer atherium) and the small hornless {Aceratherium) 

 rhinoceroses occur. The tapirs (Paratapirus) were somewhat larger ani- 

 mals than the Middle Oligocene Protapirus. Of the suoitls Palceo- 

 choerus is the precursor of the Miocene Hyotherium; the very primitive, 

 long-headed pig Doliochoerus also occurs. The small and graceful mem- 



T'fjprfr hofizonet 



>*%.,. 





Antinoithuriujn. i^rtn^ 



Unvrr-hr.ri 



Fig. 88. — Lower Oligocene fluvio-niarine formation, north of Lake Qurun, Fayum, Egypt. 

 Lower and upper horizons of the Arsinoi'therium zone. Photograph by American Museum of 

 Natural History, expedition of 1907. 



bers of the genus Coenoiherium lived in large troops in the region of 

 Pyrimont. 



Oligocene suilUnes. — Stehlin inclines to the belief ^ that both kinds of 

 true pigs (Propalceochcerus, Doliochoerus) which appear at the beginning 

 of Oligocene times in Europe are new immigrants and not descendants 

 of Choeromorus or of any other Eocene suillines of Europe (see p. 148). Of 

 these Oligocene pigs Propalceochoerus is regarded as the starting point of 

 the Old World main group of true pigs with all its branches, while Dolio- 

 choerus exhibits such striking resemblances to the peccaries (Dicotylidae) 

 of North America that Stehlin considers it very near the stem form if not 

 the actual stem form of our Oligocene group of primitive peccaries. The 



' Stehlin, H. G., Die Saugetiere des schweizerischen Eocaens, 1903-1906, p. 749. 



